This invention pertains to a novel electronic circuit which is particularly useful in an electronic control system for an internal combustion engine.
The Chrysler Electronic Lean Burn system introduced during the 1976 model year on Chrysler Corporation vehicles is a milestone in the application of electronic technology to internal combustion engines used in automotive vehicles. The Chrysler Electronic Lean Burn system has been able to achieve compliance with Federal emission standards without the use of other emission control devices such as catalytic convertors, exhaust gas recirculation (EGR), air pumps, and like devices, and in so doing, has attained a modest but significant improvement in fuel economy.
The present invention is concerned in one respect with an improvement in the Chrysler Electronic Lean Burn system. One benefit of the invention is that the number of discrete electronic circuit components is dramatically reduced. This means that economy in assembly and parts costs is realized and reliability of the system is promoted. Moreover, the circuitry may be more compactly packaged which is important where the engine controls are mounted in the limited space of the engine compartment of a vehicle. With such economy the usage of the Chrysler Electronic Lean Burn system may be expanded to encompass many engine families and vehicle lines, and this means that the Electronic Lean Burn system can be made available to a much larger number of purchasers.
In another aspect, the invention relates to a unique electronic circuit which may be used in different types of electronic engine control systems. Because of this outstanding versatility and utility, a common device embodying this unique circuit can be employed in a number of different systems; this minimizes parts inventory and stocking complexities while serving to derive the maximum benefit of mass production techniques. The circuit is particularly well suited for fabrication as an integrated circuit device using existing integrated circuit manufacturing technologies. A circuit embodying principles of the invention is especially useful in an electronic spark timing system, and its versatility permits its use in either a single or dual pick-up system and in either four, six, or eight cylinder engines.
The foregoing features, advantages, and benefits of the invention, along with additional ones, will be seen in the ensuing description and claims which should be considered in conjunction with the accompanying drawings.